|Conceptual Discussion on Free Vibration Analysis of Tension Leg Platforms|
Tension leg platforms are used for oil exploitation in deep water. The accurate and reliable responses are needed for optimum design and control of the structure. Free vibration analysis gives us a deep view of structural response and the judgment on coupling effects between degrees of freedom. In this paper the nonlinear dynamic analysis of TLP is carried out. The power spectral densities (PSDs) of responses are calculated from nonlinear responses...
Keywords: TLP; Free Vibration; Dynamic Analysis
|Experimental Investigation of Jet Impingement Heat Transfer Using Thermochromic Liquid Crystals - Dempsey, Brian Pau|
Jet impingement cooling of a hypersonic airfoil leading edge is experimentally investigated using thermochromic liquid crystals (TLCS) to measure surface temperature. The experiment uses computer data acquisition with digital imaging of the TLCs to determine heat transfer coefficients during a transient experiment. The data reduction relies on analysis of a coupled transient conduction - convection heat transfer problem that characterizes the experiment...
Keywords: FREE VIBRATION; CRITICAL LOADING; DIFFERENTIAL EQUATIONS; DEFORMATION; FREQUENCIES; LOADS (FORCES)
|Natural vibrations as cause of energy fluctuations and chemical conversions - Polanyi, M.|
Natural vibrations as energy fluctuation and chemical conversion mechanism in monomolecular reactions
Keywords: CHEMICAL REACTIONS; FREE VIBRATION; MOLECULAR ENERGY; ENERGY CONVERSION; FREE VIBRATION; MOLECULAR ENERGY LEVELS; REACTION KINETICS; VARIATIONS; VIBRATION; CHEMICAL REACTION; ENERGY CONVERSION
|Hygrothermally Induced Nonlinear Free Vibration Response of Nonlinear Elastically Supported Laminated Composite Plates with Random System Properties:Stochastic Finite Element Micromechanical Model|
This paper presents the hygrothermally induced nonlinear free vibration response of nonlinear elastically supported laminated composite plates with random system properties based on micromechanical stochastic finite element model and subjected to uniform temperature and moisture changes. System properties such as material properties of each constituent’s material, coefficients of hygroscopic expansion, thermal expansion coefficients and foundation stiffness parameters are taken as independen...
Keywords: Nonlinear Free Vibration; Micromechanical Model; Stochastic Finite Element; Hygrothermal Environment; Perturbation Technique; Nonlinear Elastic Foundations
|USSR Space Life Sciences Digest, issue 12 - NON|
This issue contains 42 papers recently published in Russian language periodicals and bound collections of four Soviet monographs. Also included is a review of a recent Soviet congress on space gastroenterology.
Keywords: FREE VIBRATION; ROTATING DISKS; VIBRATION MEASUREMENT; BENDING VIBRATION; CENTRIFUGAL FORCE; DEFORMATION; FINITE ELEMENT METHOD; MODELS
|Algebraic surface design and finite element meshes - Bajaj, Chandrajit L|
Some of the techniques are summarized which are used in constructing C sup 0 and C sup 1 continuous meshes of low degree, implicitly defined, algebraic surface patches in three dimensional space. These meshes of low degree algebraic surface patches are used to construct accurate computer models of physical objects. These meshes are also used in the finite element simulation of physical phenomena (e.g., heat dissipation, stress/strain distributions, fluid flow characteristics) required in the com...
Keywords: DYNAMIC STRUCTURAL ANALYSIS; FORCED VIBRATION; FREE VIBRATION; STIFFNESS MATRIX; DISPLACEMENT; FINITE ELEMENT METHOD; THEOREMS
|Debye-Scherrer investigations of experimentally shocked silicates - Hoerz, F.|
Breakdown of crystal lattice structure due to shock effects
Keywords: INERTIAL REFERENCE SYSTEMS; SPACECRAFT CONTROL; FREE VIBRATION; SPACECRAFT INSTRUMENTS; STANDING WAVES; VIBRATION
|Effect of tangential forces of inertia on the frequency of free oscillations in a thin cylindrical shell (o vliyanii tangent- sial'nykh sil inertsii na velichinu chastoty svobodnykh kolebaniy tonkoy tsilindricheskoy obolochki) - Finkelshteyn, R. M.|
Effect of tangential force of inertia on frequency of free oscillations in thin cylindrical shell
Keywords: CYLINDRICAL SHELLS; FREE VIBRATION; FREQUENCIES; INERTIA; THIN WALLED SHELLS; CYLINDRICAL SHELL; FREE OSCILLATION; INERTIAL FORCE; THIN WALLED SHELL
|Computational Analysis of a Pylon-Chevron Core Nozzle Interaction - Thomas, Russell H.|
In typical engine installations, the pylon of an engine creates a flow disturbance that interacts with the engine exhaust flow. This interaction of the pylon with the exhaust flow from a dual stream nozzle was studied computationally. The dual stream nozzle simulates an engine with a bypass ratio of five. A total of five configurations were simulated all at the take-off operating point. All computations were performed using the structured PAB3D code which solves the steady, compressible, Reynold...
Keywords: FREE VIBRATION; MONTE CARLO METHOD; MATHEMATICAL MODELS; LAMINATES; BEAMS (SUPPORTS); SYMMETRY; PLY ORIENTATION; STIFFNESS MATRIX; STOCHASTIC PROCESSES; FINITE ELEMENT METHOD
|Rate constants and temperature dependences for the reactions of hydroxyl radical with several halogenated methanes, ethanes, and propanes by relative rate measurements - Hsu, K.-J.|
Rate constants of 15 OH reactions with halogen-substituted alkanes, C1 to C3, were studied using a relative rate technique in the temperature range 283-403 K. Compounds studied were CHF2Cl (22), CHF2Br (22B), CH3F (41), CH2F2 (32), CHF3 (23), CHClFCCl2F (122a), CHCl2CF3 (123), CHClFCF3 (124), CH3CF3 (143a), CH3CH2F (161), CF3CHFCF3 (227ea), CF3CH2CF3 (236fa), CF3CHFCHF2 (236ea), and CHF2CF2CH2F (245ca)...
Keywords: DYNAMIC STRUCTURAL ANALYSIS; FLAT PLATES; FREE VIBRATION; MODAL RESPONSE; NASTRAN; FLUID-SOLID INTERACTIONS; PROGRAM VERIFICATION (COMPUTERS); FINITE ELEMENT METHOD; STRUCTURAL VIBRATION; ACOUSTIC EXCITATION; CYLINDRICAL SHELLS; FORCED VIBRATION
|BULLETIN OF STATIONS FOR OPTICAL OBSERVATIONS OF ARTIFICIAL EARTH SATELLITES - NON|
PRESENTED ARE NINE ARTICLES AND TWO APPENDIXES ON OPTICAL OBSERVATIONS OF ARTIFICIAL EARTH SATELLITES WHICH COMPRISE THE SEVENTH OF A SERIES OF PUBLICATIONS BY THE ASTRONOMICAL COUNCIL, ACADEMY OF SCIENCES, USSR, INTERNATIONAL GEOPHYSICAL YEAR.
Keywords: PLATES (STRUCTURAL MEMBERS); EMBEDDING; CARBON FIBERS; STRUCTURAL VIBRATION; COMPOSITE MATERIALS; RESONANT FREQUENCIES; FREE VIBRATION; VIBRATION MODE; POSITION (LOCATION); LAMINATES; EPOXY RESINS
|Single-Specimen Technique to Establish the J-Resistance of Linear Viscoelastic Solids with Constant Poisson's Ratio - Gutierrez-Lemini, Danto|
A method is developed to establish the J-resistance function for an isotropic linear viscoelastic solid of constant Poisson's ratio using the single-specimen technique with constant-rate test data. The method is based on the fact that, for a test specimen of fixed crack size under constant rate, the initiation J-integral may be established from the crack size itself, the actual external load and load-point displacement at growth initiation, and the relaxation modulus of the viscoelastic solid, w...
Keywords: MODELS; CHAINS; ERRORS; FREE VIBRATION; HELICOPTERS; MOMENTS OF INERTIA; NOISE REDUCTION; DESIGN ANALYSIS; GEARS; MANUFACTURING; NUMERICAL ANALYSIS; STRUCTURAL DESIGN; AIRCRAFT ENGINES; ASTRODYNAMICS; AUTOMOBILES
|Project SPARC: Space-Based Aeroassisted Reusable Craft - NON|
Future United States' space facilities include a Space Station in low Earth orbit (LEO) and a Geosynchronous Operations Support Center, or GeoShack, in geosynchronous orbit (GEO). One possible mode of transfer between the two orbits is an aerobraking vehicle. When traveling from GEO to LEO, the Earth's atmosphere can be used to aerodynamically reduce the velocity of the vehicle, which reduces the amount of propulsive change in velocity required for the mission...
Keywords: FINITE ELEMENT METHOD; FLANGES; LAMINATES; FRAMES; FREE VIBRATION; GRAPHITE-EPOXY COMPOSITES; MATHEMATICAL MODELS; THIN WALLS; TWO DIMENSIONAL MODELS; DISPLACEMENT; FIBER ORIENTATION
|Modeling of thermal lensing in side and end-pumped finite solid-state laser rods - Brackett, Vincent G|
An analytical expression for approximating the time-dependent thermal focal length in finite solid state laser rods was derived. The analysis is based on the temperature variation of the material refractive index caused by optical pumping of these rods. Several quantities were found to be relevant to this analysis. These quantities were the specific thermal profiles of the rods, type of optical pumping employed, type of cooling scheme employed (side and end-cooling parameters), and the specific ...
Keywords: DEGREES OF FREEDOM; MODAL RESPONSE; RUN TIME (COMPUTERS); STIFFNESS; VIBRATION MODE; DYNAMIC RESPONSE; DYNAMIC STRUCTURAL ANALYSIS; STRUCTURAL VIBRATION; COMPUTATION; EIGENVECTORS; FLEXIBILITY; FORCED VIBRATION; FREE VIBRATION
|A Numerical Simulation of Scattering from One-Dimensional Inhomogeneous Dielectric Random Surfaces - Sarabandi, Kamal|
In this paper, an efficient numerical solution for the scattering problem of inhomogeneous dielectric rough surfaces is presented. The inhomogeneous dielectric random surface represents a bare soil surface and is considered to be comprised of a large number of randomly positioned dielectric humps of different sizes, shapes, and dielectric constants above an impedance surface. Clods with nonuniform moisture content and rocks are modeled by inhomogeneous dielectric humps and the underlying smooth ...
Keywords: TRUSSES; SOLID MECHANICS; BEAMS (SUPPORTS); PLATES (STRUCTURAL MEMBERS); SHELLS (STRUCTURAL FORMS); STRAIN RATE; KINETIC ENERGY; FREE VIBRATION; STRESS-STRAIN RELATIONSHIPS; ELASTIC PROPERTIES; STIFFNESS; ENERGY METHODS; PLATE THEORY; STATIC LOADS; STRUCTURAL ANALYSIS; BENDING; SHEAR STRENGTH; FINITE ELEMENT METHOD; DEFLECTION; LATTICES; POLYNOMIALS
|EFFECT OF HINGE-LINE POSITION ON THE OSCILLATING HINGE MOMENTS AND FLUTTER CHARACTERISTICS OF A FLAP-TYPE CONTROL AT TRANSONIC SPEEDS - Moseley, W. C., Jr.|
Free oscillation test to determine hinge moment of trailing-edge, flap control surface with various hinge-line positions at transonic speed
Keywords: AIRCRAFT CONTROL; TORQUE; TRAILING EDGE FLAPS; TRAILING EDGES; TRANSONIC SPEED; FLAP CONTROL; FLUTTER; FREE OSCILLATION; HINGE MOMENT; TRAILING EDGE; TRANSONIC SPEED; CONTROL SURFACES; FLAPS (CONTROL SURFACES); FLUTTER ANALYSIS; FREE VIBRATION; HIGH SPEED; MACH NUMBER; OSCILLATIONS; TAPERING
|Modal Analysis of Embedded Passive Damping Materials in Composite Plates with Different Orientations - Kehoe, Michael|
This report presents an experimental and numerical investigation of the free vibration of cantilevered composite plates with and without passive damping. A total of seven composite material plates are considered. The lay-up sequences for the two plates without damping are [90/90/0/0], and [90/0/90/0]; the other five plates are the same as the first two with two embedded layers of passive damping material...
Keywords: FLAPS (CONTROL SURFACES); ZERO ANGLE OF ATTACK; AIRFOIL PROFILES; ASPECT RATIO; DEGREES OF FREEDOM; FREE VIBRATION; MACH NUMBER; STABILIZATION; TRANSONIC SPEED; SWEPT WINGS; THICKNESS; OSCILLATIONS; FLUTTER ANALYSIS; TRAILING EDGE FLAPS; AIRCRAFT CONTROL; CONTROL SURFACES
|MIT 2.003J Dynamics and Control I, Fall 2007 - MIT OpenCourseWare|
This class is an introduction to the dynamics and vibrations of lumped-parameter models of mechanical systems. Topics include kinematics; force-momentum formulation for systems of particles and rigid bodies in planar motion; work-energy concepts; virtual displacements and virtual work; Lagrange's equations for systems of particles and rigid bodies in planar motion; linearization of equations of motion; linear stability analysis of mechanical systems; free and forced vibration of linear multi-deg...
Keywords: dynamics and vibrations of lumped-parameter models; mechanical systems; Kinematics; Kane's method; Force-momentum formulation; systems of particles; rigid bodies in planar motion; Work-energy concepts; Virtual displacements; virtual work; Lagrange's equations; Linearization of equations of motion; Linear stability analysis; Free vibration; forced vibration; linear multi-degree of freedom models; matrix eigenvalue problems; numerical methods; MATLAB